The Effect Of Phyto-microbial Remediation To Petroleum-contaminated Alkali Soil

The petroleum hydrocarbon pollutant accumulating and leaving in environment not only damage soil productive function and the quality of agricultural products seriously, but also threaten the safety of human health and ecosystem. Due to its simpleness, low cost, good effect and no secondary pollution, bioremediation has already become the most promising technology to restore the soil contaminated by petroleum hydrocarbon. The plant is able to promote microbes to decompose petroleum hydrocarbon pollutant through root effect. Therefore, the phyto-microbial remediation can advance the effect of restoration remarkably.This research focused on the restoration of the alkali soil polluted by petroleum hydrocarbons with two efficient degrading fungi coupling with three plants(tall fescue, oats, alfalfa). The specific research findings are as the followings:In the case of the soil with petroleum hydrocarbon content of 21000mg·kg-1, the concentration of petroleum hydrocarbon decreased by 33.13% after 56 days, which was 1.69 times higher than that of CK; polyphenol oxidase activity increased 41.94% than that of CK, stimulating both the abundance and diversity of soil microbe.Taken plant height, root length and biomass as evaluation indexes, by planting tall fescue and oats in different concentrations of the alkali soil polluted by petroleum hydrocarbons, the results had found that the tolerance of tall fescue to petroleum pollution was stronger than oats, so tall fescue was the better choice about phytoremediation of alkali soil contaminated by petroleum.Selected tall fescue, alfalfa and oats three plants, we set pot tests about phytoremediation and phyto-microbial remediation treatment, after 72 days, the total concentration of petroleum hydrocarbon decreased by 54.42% for tall fescue-fungi, and by 50.98% for alfalfa-fungi, and 44.69% for oats-fungi. The soil dehydrogenase and polyphenol oxidase activity of tall fescue-fungi was the highest, followed by alfalfa - fungi, and oats - fungi. As a result, tall fescue-fungi remediation was the best choice to degrade the soil polluted by petroleum hydrocarbon.To the degradation of petroleum hydrocarbon by tall fescue-fungi, we set an orthogonal experiment on three levels and three factors, integrated petroleum hydrocarbon removal, soil dehydrogenase activity and polyphenol oxidase activity of the orthogonal test results, three kinds of factors came size range: antimicrobial dosage> nutrition soil addition > the number of washing salt. To the number of washing salt, the influence order of three levels was 2> 3> 1; to the antimicrobial dosage, the influence order of three levels was 8%> 4%> 2%; to the nutrition soil addition, the influence order of three levels was 7%> 4%> 1%.Therefore, the optimal design was that the number of washing salt was 2 times, antimicrobial dosage was 8% and nutrition soil addition was 7%.